Drill



A. L. HAWKESWORTH.

DRxLL. y APPLICATION HLED NOV.2l, 1921.

mmm Aug. 22, 1922.

nutren Asrgras ARTHUR L. HAWKESWORTH, BUTTE, MONTANA.

DRELL.

ineens?.

Application filed November 21, 1921.

To all whom t may concern.'

Be it known that l, ARTHUR L. HAWKES- WORTH, a citizen of the United States, residingat Butte, in the county of Silverbow and State of Montana, have invented certain -new and usefulV Improvements in Drills, of

which the following is a specification.

The present invention has relation to improvements in drills having detachable bits, the object sought being to provide simple and effective interlocking means between the bit and shank whereby the bitmay be retained in place while in working position.

A further object is to provide a drill havingto present the small end of the cooperating tongues and grooves on bit and shank; Fig.

2 is a side elevation of the drill; Fig. 3 is an elevation turned through an angle of 45 0 or midway between the positions shown 1n Figures l and 2; Fig. 4 is a detached elevational view of the bit vturned to present the narrow ends of tongue and groove; Fig.

5 is adetached elevational view 'of the shank i the bit; Fig. 8 is a top plan of the bit showing the arrangement of the cutting edges.

Referring to the drawings, l represents a drill bar or shank provided with a central passage-way or duct a for the flow of water usually employed in drilling operations as well understood in the art. The shank is provided at its bit supporting end with a transverse 'dove-tail tongue 2 disposed across the shank to one side of the axis thereof, and a transverse dove-tail groove 3 adjacent to the tongue and on the otherside of said axis.A The side walls of thelv tongue taper in the general direction toward the cutting end of the drill, and the side walls of the Specification of LettersPatent. Papeimbd Aug., 229 1922.

Serial No. 516,782.

groove taper in the opposite direction or away from the cutting end of the drill. The tongue and groove have the bounding wall b in common, which is substantially twice the width of the outer bounding Wall c of the tongue and outer bounding wall (Z of the groove, the wall c being determined by the offset e, and the wall al by the top'face f thereof, said offset e and top face f being in the same plane, which is parallel with the bottom face g of the groove and top face h of the tongue.

Adapted to be passed across the shank 1 is the bit 4, the samebeing provided with two converging duct-s a', a, said ducts coming together at their intersection with duct o of the shank when the bit is in workingposition on the shank. The bit is provided with a transverse tongue 5 shaped to fit groove 3 of the shank and a transverse groove 6 shaped to receive tongue 2 of said shank. The tongue 5 and groove 6 have the boundi ing wall z' in common, said wall extending across the axis of the drill. The outer bounding walls j of the tongue and lc of thegroove, however, are about one-half the width of wall z', being determined by the plane of offset m and Atop face n of wall is, said offset and top face being in a common plane parallel with the bottom face 79 of the tongue 5 and top face r of the groove 6. From the foregoing the tongue and groove formations on shank and bit will be seen to be exact counterparts of each, Vbeing reversed. however. to permit their engagement one with the other. This engagement may be readily accomplished by simply siipping the narrow end of tongue 5 into the wide end of groove 3, whereupon the narrow end of tongue 2 will enter the wide end of groove 6. The bit may now be moved across the axis of the shank until the tongues are wedged into their corresponding grooves, at which time the top faces f and fn, will bear against the offsets fm, and e respectively, and the shank and bit are in operative relation. Obviously the exact details of the above construction need not be adhered to, as they may be modified without departing from the spirit of the invention. By virtue 'of the inclination of the tongues and grooves on both shank and bit, said bit will be wedged tighter as. the drill is in operation, however. in order to detach the same it is merely necessary 'to give a slight knock on the bit at the narrow end of tongue 5 to loosen same,

lloo

whereon it may be readily removed and a new bit substituted.

The bit 4 is formed with a series of cutting legs 7 (four in the present case) said legs extending d/own a short distance'onto the shankl/an'd terminating at their outer ends in beveled cutting edges 8. Recesses yprovided and-the bevel surfaces u, u .con-

tinued until they intersect, the cutting edge would continually get Wider as it became worn, yand would soon cease to cut. In the present construction the cutting edge'cannot get wider than the thickness of the wall w between the recesses t until the wall has been entirely worn away. Theperipheral surfaces of the cutting legs are dished out or concave at v so that after the bit has become worn there Will be less friction against the sides of the hole than there-would be if the depressions were omitted. With the legs 8 dished the friction would only exist around the edges of the legs instead of over the entire surface. A

The recesses t also result in the'formation of circumferentially extending wings w,w, at the ends of the cutting legs 7, said wings 'assisting in drilling the hole when the drill is o erated by percussion.' 4

aving described my invention, I claim:

11. In combination with a shank terminating at one end in a Itapering tongue and having a tapering groove adjacent to the tongue, the tongue and groove being on opposite sides of a plane passing through the axis of the shank acutt'ing tool movable across the axis ofthe shank and provided with a groove and tongue adjacent thereto for cooperating with the tongue and groove on lthe shank when tool and shank are'in operative relation.

2. In combination with a shank terminatin at one end in a tongue disposed on one si e of a lane passing through the axis of the shan the side walls of said, tongue tapering in the general direction away from the shank, a groove formed in the shank adjacent to -the tongue and on the opposite side of said tongue, the side walls of said lgroove tapering in the general direction toward the shank, a cutting tool movable across the axis of the shank and provided with a groove and tongue for cooperating with the tongue and groove on the shank when tool and shank'are in operativel relation.

' 3. In combination with a shank terminat-v ing at one end in a dove-tail tongue, thev v i side walls of which taper in the general direction away from the shank, said tongue ing at one end in a tapering tongue and having a tapering groove adjacent to the tongue, a cutting tool movable aoross the axis of the shankA and provided with a groove and tongue adjacent thereto for cooperating with the tongue and groove on the shank when tool and shank are in operative relation, the outer bounding wall of the groove being of lesser dimension than the inner wall thereof, and the outer `bounding wall of the tongue being of lesser. p .90

dimension than the inner wall thereof.

5. A drill bit provided withxa plurality of cutting legs', the bit being recessed byetwe'en said legs to form comparatively thin walls at the ends of the legs, the outer ends of said walls forming cutting edges, and

the peripheral surfaces of said 1egs be j ing recessed.

6. A drill bit provided with cutting legs terminating at their outer ends in .cutting surfaces having circumferentially extending wings the peripheral surfaces of said legs being recessed.

7. A drill bit provided with cutting legs terminating at theirouter ends in cuttin surfaces having circumferentially exten ing wings, the bit being recessed between the legs and the peripheral surfaces ofsaid legs being-recessed.

r:In testimony whereof I hereunto affix my signature.

ARTHUR L. HAwKEswoRrn 

